In the aeronautics field, utilizing hot air, taken at the location of the turbojet engine compressors of an aircraft to supply the air conditioning circuits of said aircraft, is known. As the air conditioning circuits are destined for the cockpit and passenger cabins, it is necessary to cool this hot air before injecting the air into said circuits.
For this purpose, a heat exchanger is used, in which a flow of hot air, taken at the level of a turbojet engine compressor, crosses a flow of cold air, taken at the outlet of a turbojet engine fan. The flow of cold air and the flow of hot air circulates inside a heat exchanger housing in such a way that a calorific exchange may take place. At the outlet of the heat exchanger housing, the hot airflow is partially cooled and sent in the direction of the air conditioning circuit. As for the cold airflow, as it has allowed cooling, it is discharged to the outside.
A major disadvantage of current heat exchangers is their bulkiness. In fact, the heat exchanger is generally disposed on an upper face of an attaching mast that connects the turbojet engine to the aircraft wing system. Because of the position of the mast above the turbojet engine, the cold air and hot air inlet lines must cross the viable structure of the mast. The passage of cold air and hot air inlet lines in the viable structure, or structure box, of the mast necessitates reinforcement of the mast structure at the level of the passage of said air inlet lines. This tends to notably weigh down the structure.
To mitigate this disadvantage, it is possible to arrange cold air and hot air inlets in such a way that the hot air inlet line crosses a pyramid of the mast, which is a hollow structure situated in front of the mast structure box. The cold air inlet line passes above the pyramid of the mast and therefore does not cross said mast.
However, such a solution is difficult to implement. In fact, the hot air inlet line is situated under the cold air inlet line, while the cold air and hot air inlet lines respectively penetrate in the heat exchanger housing by the lower face and the front face of said housing. Therefore, the cold air inlet line may impede the passage of the hot air inlet line.